text: Potential disadvantages of noise barriers include:
  * Blocked vision for motorists and rail passengers. Glass elements in noise screens can reduce visual obstruction, but require regular cleaning
  * Aesthetic impact on land- and townscape
  * An expanded target for graffiti, unsanctioned guerilla advertising, and vandalism
  * Creation of spaces hidden from view and social control (e.g. at railway stations)
  * Possibility of bird–window collisions for large and clear barriers